Pandora’s Box: Waging war on invasive plants in Maine is a full-time job

Posted June 29, 2014, at 10:24 a.m.
Last modified June 29, 2014, at 12:15 p.m.

FARMINGTON, Maine — Living next to a cemetery isn’t a great place to be unless you happen to be an invasive plants and trees educator like Patty Cormier.

Her yard beside Riverside Cemetery on Route 2 in Farmington is a veritable Pandora’s box of invasive plants and trees. Birds and the prior owner of their property, along with people who unwittingly planted invasives at their loved ones’ graves or left wreaths made with the seed-carrying berries of invasive plants, have doomed their yard’s native plants and trees.

“There’s about 2,100 plant species in Maine, and about a third of those are nonnative, and then a small portion of those are invasive,” said Cormier, one of eight district foresters with the Maine Forest Service. Her district is Franklin and Somerset counties.

Invasive plants, whether or not they pose a danger, can crowd out native species and some, such as bittersweet, send out vines that strangle and destroy native trees.

Of those invasives, her yard has Asiatic bittersweet, an autumn olive, a burning bush, Japanese honeysuckle, and new this spring, a Japanese barberry plant.

Down through the woods behind their yard and along the Sandy River are dangerous giant hogweed invasive plants, mixed in with the non-dangerous native cow parsnip plants they resemble. Contact with sap from giant hogweed followed by sun exposure can cause third-degree burns, Cormier said.

“The actual definition of ‘invasive’ is if it does environmental harm, economic harm and harm to human health, then that’s what makes it invasive,” Cormier said.

“Look at dandelions,” she said. Depending on what you think, some would say they’re invasive, but they’re a native. Look at the lupines in Bar Harbor. If you’re an invasive, it pays to be pretty and that’s what it comes down to.”

Invasives have no natural predators and they adapt much better than native species, she said.

“One identification feature of many of the plants is to look in the spring,” she said. “They’re the first ones out, so that’s an advantage. They occupy the site, and then they’re the last [plant] with their leaves on in the fall.”

The Cormiers have lost four to five feet of their lawn to bittersweet that is quickly gobbling up an oak, an ash, a poplar and a cherry tree. Bittersweet vines are killing a young sumac by strangling its trunk.

The poplar tree was bent way over, its top nearly touching the lawn from the weight of the bittersweet vines choking its trunk and branches.

“We’re right next to the graveyard,” Cormier said. “Therefore, we get everything. It’s very helpful when I do workshops, too, because I can get samples from right out here in my backyard.

“Bittersweet, it’s got a very pretty red berry. People use it for wreaths all the time. So people bring the wreaths home, it warms up, the berries fall off, or they throw it outside on the compost pile — and now you’ve started bittersweet in your yard.”

Most invasive plants and trees thrive on soil disturbance, such as a property owner harvesting timber.

Bittersweet vines can be aged like trees by cutting the trunk and counting the rings, she said. While working at a woodlot, she cut a bittersweet vine and counted the rings. It was 35 years old.

“And guess when the last [timber] harvest there was — 35 years ago,” Cormier said.

Clifford Woods, a land trust property located near downtown Farmington, is overrun with bittersweet, Cormier said.

Last summer, Cormier and her husband waged war on the rapidly growing, aggressive bittersweet vines that are overtaking their hedge of trees and shrubs that separates their yard from the cemetery.

“We cut a lot of this last summer and it’s still here,” she said.

So Cormier is taking that war to a new level. She strews the young bittersweet plants she uproots across the limbs of a tree in full view of the remaining bittersweet as a not-so-subtle message.

“You’re supposed to pull it and hang it in a tree to warn the remaining bittersweet,” she said, doing just that with about a foot-long bittersweet that sprouted this month.

Cormier next identified a huge growth on the side of her house fronting Route 2 as a burning bush plant. It was flanked by two azalea bushes, one of which was being crowded out by the invasive. The burning bush was also blocking sunlight to a small oak tree and a small maple tree under the oak.

“It turns that bright red in the fall; that’s why people plant it and, of course, why nurseries sell it,” she said of the burning bush.

“And the birds love the berries. Therefore, [the seeds] get spread. So it’s a matter of seeing it and saying, ‘I don’t want to plant that.’ It’s not invasive right here. I mean, it’s not taking anything over, but I’m certainly adding to the problem because of the birds.”

To view the full story, go to


Recommend this article


Similar Articles

More in State